Biodiesel may be used as an alternative fuel or an additive for combining with petroleum or fossil-based liquid fuels. A typical use of biodiesel may be the replacement of or blending into Diesel #2, which itself is a crude mineral oil refining process distillate. Diesel #2 may generally be used as fuel in internal combustion power plants used in vehicles, power generation equipment, and the like. Biodiesel may be seen as a renewable, biodegradable, sustainable fuel (e.g., being obtained from replenishable sources such as oil seed crops and the like) that produces 85% less greenhouse gas emissions in comparison to non-renewable, generally non-biodegradable, petroleum-based Diesel #2 usage. Similarly, biodiesel may be further refined via hydrocracking to produce short-chain fatty acids and esters for use in turbine fuels.
To create biodiesel, generally a raw, renewable, source of fatty acids may be used as a feedstock (e.g., such as seed oil that is refined from crushing of seeds). As substantially shown in FIG. 2, the biodiesel feedstock is a triglyceride (namely a glycerin molecule with 3 fatty acid carbon chains [generally of variable lengths] attached to it.) Transesterification means, known to those who have skill in the art, to react the triglyceride feedstock with an alcohol [e.g., methanol, ethanol, etc] in the presence of the base catalyst such as sodium hydroxide (NaOH) potassium hydroxide (KOH) or sodium methylate (NaOCH3). The alcohol reacts with the fatty acids to form the mono-alkyl esters (or biodiesel) and crude glycerin (a/k/a glycerine, glycerol). The mixture of mono-alkyl esters (or Fatty Acid Methyl Esters, also known by the acronym F.A.M.E. or FAME or other similar alkyl esters) and crude glycerin may then be substantially separated into a biodiesel (e.g., various FAME or mono-alkyl esters fractions) portion and a glycerin portion. The separated out portion of the various FAME fractions then generally undergoes a product purification to bring the FAME/biodiesel portion to desired industry standards for use as fuel (such as ASTM D6751 and the like).
Some of the issues relating to such biodiesel performance are generally a function of its feedstock's fatty acid profile. For example, biodiesel fuel made from Coconut oil has a very high Cloud Point and Gel Point in comparison to other biodiesel made from other feedstocks because it is primarily composed of saturated fatty acid esters. These physical characteristics may cause the biodiesel made from coconut oil feedstock to undergo a partial phase change at above acceptable temperatures leading to higher viscosity and crystallization, interfering with its use in engines, and possibly requiring the introduction of expensive gel point lowering additives into the resultant biodiesel.
Some feedstocks have high amounts of saturated fatty acids present giving their resulting biodiesel fuels improved oxidative stability, making the biodiesels less likely to require oxidative stabilization additives. Such resulting biodiesel fuels are suitable in more tropical climates. Biodiesel fuel manufactured from oils such as flax have a very different effect on biodiesel functionality. Flax oil, for example, is very high in highly unsaturated fatty acids (HUFA). Biodiesels made from such fatty acids have very low operating temperatures and can work under relatively cold conditions but are oxidatively unstable over time and in high heat conditions making them unsuitable for fuel use without excessive fuel stabilizers.
What is needed therefore is a high volume, separation process or methodology that not only isolates, refines and removes from the biodiesel, the various FAME fractions in high purity that are commercially desirable compounds apart from their original fuel usage but also allows such purified fractions to be further treated and combined to form new fuels (e.g., aviation fuel) having better fuel characteristics than the original mixed fraction biodiesel from transesterification. Such FAME fractions could include Omega 3 polyunsaturated FAME, mono unsaturated FAME, and saturated FAME.
The high purity Omega 3 polyunsaturated FAME fraction could have further demand in the cosmetic and neutraceutical industry. The Omega 3 (typically alpha-linolenic acid [ALA]) FAME fractions may be classified as a member of the essential fatty acid group, so called because they cannot be produced within the human body and must be acquired through diet. Omega 3 FAME is shown to reduce serum cholesterol and is used in the neutraceutical industry in dietary supplements. Omega 3 FAME also may be highly sought out by the cosmetics industry as binders, as they are close in composition to skin oils.
The saturated and unsaturated FAME fractions may be used to provide a biodiesel with performance characteristics for a multitude of weather conditions, as well as be an additive for an aviation fuel, lubricant, or biodiesel blend, and heating oils. Unsaturated FAME such as monounsaturated fatty acids (i.e., MUFA or omega 9) and polyunsaturated fatty acids (i.e., PUFA or omega 6) are typical of standards used by the European Union and North American FAMEs found in such a biodiesel feedstock per ASTM D6751 biodiesel test protocols. The Omega 6 and Omega 9 FAME components found in the biodiesel may be more likely to undergo oxidation generating the presence of epoxies and ketones in the biodiesel. The presence of these epoxies and ketones could require the use of stabilization additives in the biodiesel to allow it to function properly in its intended use. The saturated FAME, having a high cloud point and the omega 3 (HUFA) generally having a poor oxidative stability are typically minimized to pass ASTM D6751 biodiesel fuel specifications.